Evaluating wetland mitigation banks...

A new study has evaluated wetland mitigation banks in restoring, creating, and preserving habitat. The results show that regulators need to do a better job in making sure that bank operators comply with the Clean Water Act's stated goal of 'no net loss of wetlands.' 

A background on wetland mitigation...
If you've worked in the conservation field, you're probably pretty familiar with wetland mitigation - a practice that's required under the Clean Water Act for those who want to negatively impact wetlands for some reason (e.g. to build a house or a road). The act requires that you avoid and minimize impacts and in the case where impacts are unavoidable that you compensate for the loss by preserving, restoring, and/or creating wetlands. Since most homebuilders aren't in the wetland restoration business, it creates an opportunity for private businesses to do the work for you - at a price. Unfortunately, many mitigation projects have suffered from a variety of problems over the years - the most severe being their small size and isolation from other wetlands.

Mitigation banks are typically for-profit enterprises that do wetland preservation, restoration, and/or creation on a large scale ahead of time. They then are able to sell mitigation credits to those in need. Regulators have largely embraced this model because by implementing mitigation over bigger areas and incorporating larger-scale planning, management, financial resources and scientific expertise, mitigation banks seemingly addresses many of the problems that plagued past projects.

Evaluating the success of wetland mitigation banks...
The key question, of course, is whether mitigation banks are actually doing a good job. The researchers in this new study addressed this issue by looking at whether mitigation banks in Florida were meeting their permit requirements. On the surface, the results seem not too bad. Interviews with agency staff found that 41% of the banks had either reached final success criteria or were trending in that direction. Meanwhile, 17% were not trending towards success (for the other 42% it was too early to tell).

But what does this really tell us about wetland conditions and whether mitigation banks are truly achieving the Clean Water Act's stated goal of no net loss of wetlands - unfortunately, not too much. The researchers also looked at the specifics of the banks' success criteria and found them lacking in detail. While all banks were required to meet set hydrological criteria, those criteria were tied to completing restoration or enhancement activities (e.g. ditch filling, culvert installation) rather than achieving a specific ecosystem response or functional equivalency. Similarly, the designation of reference standard conditions (i.e. target communities) was absent in over 50% of the permits even though it's a standard practice of restoration. The study also found that while 76% of the banks addressed vegetation criteria in permit success requirements, only 38% addressed wildlife and 28% addressed prescribed fire. The researchers offer the following recommendation to agency regulators:

"Implementing monitoring plans that specifically spell out ecological success criteria (e.g. statistical similarity to a reference site, specific scores on designated assessment methods) and awarding credits only after said success criteria are met could improve the ecological performance of banks by increasing adaptive management implementation."

--Reviewed by Rob Goldstein

Reiss, Kelly, Hernandez, Erica, & Brown, Mark (2009). Evaluation of Permit Success in Wetland Mitigation Banking: A Florida Case Study Wetlands DOI: 10.1672/08-148.1